Abstract

Contributed Talk - Splinter GalaxyClusters   (MW-1050)

Probing hot baryons beyond the virial radius of massive halos

Xiaoyuan Zhang
Max Planck Insitute for Extraterrestrial Physics

The hot gas in the outskirts of galaxy cluster-sized halos, extending around and beyond the virial radius into nearby accretion regions, remains among the least explored baryon components of large-scale cosmic structure. In this talk, I will present recent progress from the eROSITA All Sky Survey in probing the hot gas in these low-density regions. The stacking of 680 galaxy clusters in the low-redshift Universe greatly expands understanding of gas distribution in and beyond halo outskirts. The stacked surface brightness profile reveals significant X-ray emission out to 2*r200m (about 4.5 Mpc). The subsequent modeling discloses the position of the cluster boundary as well as the gas density and gas fraction out to r200m. Meanwhile, the density profile and its slope indicate that feedback processes have played an important role in shaping the outer atmospheres of massive halos.